Determination of levamisole in animal tissues using liquid chromatography with ultraviolet detection.

An efficient and sensitive liquid chromatographic method is described for the determination of the anthelminthic drug levamisole, in muscle, liver, kidney and fat of sheep, pigs and poultry, using thiabendazole as internal standard. Samples were extracted by homogenizing with chloroform, and were applied to Supelco Si solid-phase extraction columns and eluted with methanol. Chromatographic analysis was performed on a LiChrospher 60 RP-Select B column using methanol/ammonium acetate buffer 0.05 M (55/65, v/v) as mobile phase and reading at 220 nm. The quantification limit for the assay was 4 ng/g. Mean recoveries were about 84% for liver, 85% for kidney, 89% for muscle and 84% for fat. The assay has been used for statutory testing purposes.

Planar chromatographic and liquid chromatographic analysis of thiamphenicol in bovine and human plasma.

A planar chromatographic (PC) method was developed to determine thiamphenicol in human and bovine plasma with florphenicol as internal standard. The performance of the method was compared with that of a liquid chromatographic method. Recovery of extraction method developed for plasma was 81.51 +/- 2.85%. Reproducibilities of the PC assay performed with various PC plates were also good.

Thin layer densitometry in the quantitative assay of drugs. Note V--Assay of reserpine and chlorthalidone in the presence of the potential impurities of their solid pharmaceutical forms.

Densitometric detection of compounds separated by thin layer was applied to the assay of a mixture of reserpine and chlorthalidone and their possible impurities. The method of analysis gave satisfactory results in the quality control of pharmaceutical preparations. Good results were obtained in urine tests for the detection of chlorthalidone, reserpine and methylreserpate. The times for the development of fluorescence in reserpine and methylreserpate directly in the chromatographic plate, are also described.

Thin-layer chromatography and densitometry in drug assay: comparison of methods for monitoring valproic acid in plasma.

A thin-layer chromatographic (TLC) method is described for the assay of the anti-epileptic drug, valproic acid, in plasma. The use of high-performance (HPTLC) plates gave sensitive detection limits (4.87 micrograms ml-1) for derivatives of valproic acid and the reproducibility on the same or different plates was good. Comparison with high-performance liquid chromatography showed a similar performance of plate and column.

Drug analysis by near-infra-red reflectance spectroscopy. Determination of the active ingredient and water content in antibiotic powders.

Near-infra-red reflectance spectroscopy is used to determine the active ingredient concentration and water content of an antibiotic powder (ceftazidime pentahydrate). The validity of predictive models for active ingredient concentrations and water content, constructed by means of the multiple linear regression technique is discussed. A procedure is devised for the analysis of production samples, which, on account of the very limited range of concentrations, prove a difficult fit to the above-mentioned model. The results obtained in testing formulation samples from 1 year's industrial production are used to illustrate the potential of the technique.

[Densitometric control of the degradation products of vitamin B1 and calculating activation factors]. / Contrôle densitométrique des produits de dégradation de la vitamine B1 et calcul des facteurs d'activation.

The authors perfect a TLC method with densitometric detection for the determination of vitamin B1 in the presence of its hydrolytic and oxidation products. The decomposition process and the proportions of products formed in the ampoules under different conditions of temperature/time treatment are also investigated and the activation factors (z and FO) of thiamine thermical decomposition, for their application in sterilization processes.

Application of NIRS to the quantity control of pharmaceuticals ketoprofen assay in different pharmaceutical formulae.

The possibility of using reflectance NIRS to assay 2-(benzoylphenyl)-propionic acid (Ketoprofen) in solid-state and gel preparations is investigated. The number of samples and amplitude of the percentage content distribution of the samples is examined in order to define the best possible calibration system.